Carrier route record

DLPHX→SLC

Delta Air Lines · Phoenix to Salt Lake City

Flights: 1,708
Period: July 2025 to June 2026
Share of route: 30%
Carriers: 6

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.

Delta on PHX to SLC earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 13 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 1,708 flights. The strongest carrier on the route with a full sample, Frontier Airlines, flew 677 at 83.6% on time.

Set against the rest of the country, Delta's PHX to SLC record is 13 points better than the US average of 77.6%. That gap is worth roughly 128 fewer late arrivals for every thousand flights.

On time

90.4%

Arrivals under 15 minutes late, of 1,696 completed flights

Avg delay

75 min

Across delayed arrivals only, not all flights

Cancelled

0.59%

National rate is 1.81%

Whole route

83.0%

Every carrier on PHX to SLC, 5,757 flights

These figures cover 1,708 flights between July 2025 and June 2026. The median arrival is 12 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.

Carrier by carrier

Delta against every carrier on PHX to SLC

Delta flew 1,708 of the 5,757 flights on PHX to SLC, about 30% of it. Its 90.4% on time is 7 points better than the route as a whole, which runs 83.0%. Ranked by on-time rate it is first of six carriers on the route, where the range runs from Delta at 90.4% to Southwest at 75.5%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Frontier Airlines arrives on time 83.6% of the time; Southwest Airlines manages 75.5%. Sample sizes sit next to every figure, because a two-point gap across 1,858 flights means less than a ten-point one.

On-time performance by carrier on PHX to SLC
Airline	Flights	On time	Avg delay	Cancelled	Grade
Delta Air Lines (this page)	1,708	90.4%	75 min	0.59%	A+
American Airlinesthin sample	266	86.7%	70 min	0.38%	A+
Frontier Airlines	677	83.6%	78 min	1.77%	B
Envoy Airthin sample	89	83.1%	46 min	0.00%	B+
SkyWest Airlines	1,159	83.1%	67 min	0.26%	B+
Southwest Airlines	1,858	75.5%	48 min	0.32%	B+

Frontier leads Southwest by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.

Flight by flight

Delta flight numbers on PHX to SLC

Departure window

When Delta runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 12 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am365 flights97.0%
8am–11am313 flights94.2%
11am–2pm289 flights88.4%
2pm–5pm126 flights88.8%
5pm–8pm543 flights85.2%
8pm–5am72 flights91.7%

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 97.0% of the time, against 85.2% for the evening window. That is 12 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 543 flights scheduled in it.

Across the year

Delta on PHX to SLC through the year

Darker means more delays. Figures are on-time percentages.July best, October worst

December is the weak month at 87.1% on time, against 95.2% in July. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. December was the busiest month here, with 150 flights.

Across the week, Wednesday is the strongest day at 94.2% on time and Monday the weakest at 86.9%. 7 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 59% of the 12,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Late-arriving aircraft
59%
Carrier
33%
National Airspace System
4%
Extreme weather
3%

59% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 12,000 reported delay minutes here, that single category outweighs weather by 20 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit. The split is drawn from 12,161 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 97.0% on time here.

Cancellations are rare at 0.59%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

Badly late arrivals are rare here: only 3.7% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 507 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg runs 87.9% on time across 1,708 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,708 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking Delta on PHX to SLC

Put together: avoid the 5pm–8pm departure. It runs 85.2% on time against 97.0% for the 5am–8am slot, and that 12 points is the largest single thing you control here. Frontier Airlines is the strongest operator if the fares are close. 1,696 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures